Fuel system components employed in some modern ground and aviation equipment rely on the fuel passing through them for lubrication of sliding contacts. Some of these components experience extreme temperature and pressure conditions in operating engines. One such component is the fuel injector used in diesel engines.
One way to examine the efficacy of fuel compositions as lubricants and the resistance of materials to the wear mechanisms experienced in fuel injectors would be to construct full-scale working units and run them in test engines, examining them afterwards for wear. This approach is both costly and time consuming. It is of great utility in the transportation industry to predict the efficacy of fuel compositions in providing lubrication and the wear resistance of various materials of construction without having to construct and operate full scale equipment under conditions duplicating the operating conditions to which the equipment would be subject when in use.
Typical equipment used for testing lubricity uses a mechanism to impart motion between two samples of material with the lubricant of interest interposed between the samples. The lubricating ability of the lubricant under study is determined either by studying the rate of wear of standard sample materials with different lubricants under the same conditions of load and motion, or to measure the amount of torque transmitted between a driving mechanism holding one sample and a driven mechanism holding the other sample when a given lubricant is interposed between the driving and driven samples. Both schemes have been employed in bench top scale equipment and attempts have been made to correlate the results thus obtained with the results obtained from employing full-scale equipment in an operating engine.
Such testing equipment include a sealed chamber that affords reciprocating contact between test surfaces while maintaining the lubricant inside the sealed chamber. Mechanical seals, such as O-rings or other gasket materials, have proven ineffective when testing corrosive lubricating media samples. Corrosive lubricants break down mechanical seals allowing the seals to become an additive of the lubricant. A need exists for an apparatus that allows for testing corrosive lubricating media while also maintaining a sealed chamber under pressure and at elevated temperatures during operation.